城区森林与乡村森林近地层臭氧浓度变化规律的对比研究

Abstract

PDF HTML阅读 XML下载 导出引用 引用提醒 城区森林与乡村森林近地层臭氧浓度的变化规律对比 DOI: 10.5846/stxb201301150104 作者: 作者单位: 南京大学 生命科学学院,南京大学 生命科学学院,南京大学 生命科学学院,南京大学 生命科学学院 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金（31000226） Comparison of near-ground ozone concentrations between urban and rural forests Author: Affiliation: School of Life Science, Nanjing University,,,School of Life Science, Nanjing University Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:在基于城乡间环境梯度而发展的以“空间代替时间”研究陆地生态系统对全球气候变化响应的方法中，近地层臭氧的干扰是决定“城市自然大实验场”是否可行的最重要因素之一，但是城、乡近地层大气臭氧变化规律的研究却非常薄弱。以位于南京市中心的城区森林和镇江市下蜀的乡村森林为例，于2011年6月至2013年1月间，监测了近地层大气臭氧浓度，以及光照、温度、湿度等的变化动态，比较了两地臭氧浓度的日变化、季节变化规律。结果表明，城区样点与乡村样点相比，年平均气温高0.93℃，而相对湿度和光照强度最大值分别低3.37%和13108.77 lx。说明选择的样点有很好的代表性，反映了城、乡间典型的温湿度差异。而臭氧浓度的监测结果表明，乡村样点年平均臭氧浓度高于城区样点，但是生长季节（夏季）两样点间的差异不显著；城区和乡村样点一年中大于40 nL/L的时间分别是14%和13.9%；两样点AOT40的差异不显著。结果表明，虽然大部分时间乡村样点的近地层臭氧浓度高于城区样点，但是对研究陆地生态系统对全球气候变化响应的“城市自然大实验场”干扰较小。 Abstract:Numerous studies have shown that ecological factor changes along the spatial gradient of urban and rural sites have a strong similarity to the temporal gradient of global change. Therefore, based on environmental gradients between urban and rural areas, a space-for-time substitution experiment called the "urban nature experimental field" method is developed to research the response of the terrestrial ecosystem to global climatic change. In recent related studies, the characteristics of ecological factors in urban and rural areas were observed in many cities around the world, most of which were focused on temperature and carbon dioxide. However, some reports showed that the disturbance from near-ground ozone was one of the most influential factors in determining the effectiveness and applicability of the method. To date, little research has been carried out to monitor and identify the spatial variation of near-ground ozone concentrations along the urban-rural gradient. Therefore, we selected the following urban and rural forest sites: the urban site in Qingliangshan Park near the urban center of Nanjing, and the rural site in Xiashu at 41.7 km distance from the Nanjing city center. We monitored near-ground ozone concentrations, as well as light intensity, air temperature and humidity, from June 2011 to January 2013. We also compared diurnal and seasonal variation of ozone concentration. The results suggest that there were significant differences of temperature, humidity and maximum light intensity between the two observation sites (P < 0.001). Compared to the rural forest site, the urban site had an average 0.93℃ higher temperature, 3.37% lower humidity, and 13108.77 lx lower maximum light intensity. This shows typical differences of temperature and humidity between urban and rural sites, and implies the representativeness and appropriateness of the selection of the two monitoring sites. At the urban site, an annual average of 19.95 nL/L in near-gound ozone concentration was observed, slightly less than that at the rural site (23.24 nL/L). The difference pattern of ozone concentration between the two sites varied seasonally. In autumn, winter and spring, significantly higher seasonal average ozone concentrations were observed at the rural forest site, relative to the urban site (P < 0.01). In summer, there was no difference between the two sites (P > 0.05). Relative frequencies of ozone concentrations in excess of 40 nL/L were 14.0% and 13.9% at the urban and rural sites, respectively. AOT40 (accumulated ozone exposure over a threshold of 40 nL/L) values at the urban and rural forest sites were 0.968×10 h and 1.259×10 h, respectively. There was no significant difference in AOT40 values between the two sites.Our study demonstrated that near-ground ozone concentration in the rural forest was generally higher than that in the urban forest. However, there was no significant difference during summer in the city of Nanjing, the season when plants grow vigorously and are susceptible to damage from near-ground ozone concentrations. We conclude that the disturbance of plant growth from variation of near-ground ozone concentrations between the urban and rural sites was negligible in the urban space-for-time substitution experiments. 参考文献 相似文献 引证文献